Revert "Adds an invert method to promises that returns a "inverted" promise that is resolved when the underlying deferred is rejected and rejected when the underlying deferred is resolved."
This reverts commit 4e975430510f443ef76a90d077bc8956fb8b8cc0.

Fix a some inaccuracies in the original test case for #7912.
- Use fresh div instead of one outside the test-fixture
- make sure the empty string test tests actually that (not 0% 0%)
- actually test for < -10000 (#7193)
- fixed some whitespace issues

Fixes #7912. Make sure .cur() only returns 0 as fallback value when it needs to ("", auto, undefined, null).
This change makes .cur() more .cssHooks friendly. .cur() now returns the unmodified value by
.css() if it isn't a number, number-alike or a value that needs a fallback to 0.
This way fx.start doesn't need to be recalculated for complex values.

Fixes #7922. Copy the donor event when simulating a bubbling submit in IE so that we don't accidentally stop propagation on it. Remove a bunch of return statements that could also cancel the event. DRY out the liveFired change from #6359 by moving it to the trigger() function.